condition mean min max ZT0-3 40.47928584 38.62794616 42.33062552 ZT4-7 25.8176278 23.69653305 27.93872255 ZT8-11 28.014392105 27.74351551 28.285268699999996 ZT12-15 7.9845311605000004 3.8324918834999995 12.136570437500001 ZT16-19 1.95004122525 1.6234946605 2.27658779 ZT20-23 2.61237069875 2.5934788485 2.6312625489999997